Functional olfactory receptors — the sensors that detect odors in the nose — are also present in taste cells found on the human tongue, according to new research published in the journal Chemical Senses.
Malik et al provide the first direct evidence of the presence of functional olfactory receptors in mammalian taste cells. Image credit: Phichit Wongsunthi.
While many people equate flavor with taste, the distinctive flavor of most foods and drinks comes more from smell than it does from taste.
Taste, which detects sweet, salty, sour, bitter, and umami molecules on the tongue, evolved as a gatekeeper to evaluate the nutrient value and potential toxicity of what we put in our mouths.
Smell provides detailed information about the quality of food flavor. The brain combines input from taste, smell, and other senses to create the multi-modal sensation of flavor.
Until now, taste and smell were considered to be independent sensory systems that did not interact until their respective information reached the brain.
“Our research may help explain how odor molecules modulate taste perception,” said Dr. Mehmet Hakan Ozdener, senior author of the study.
“This may lead to the development of odor-based taste modifiers that can help combat the excess salt, sugar, and fat intake associated with diet-related diseases such as obesity and diabetes.”
Using genetic and biochemical methods to probe the taste cell cultures, Dr. Ozdener and his colleagues found that the human taste cells contain many key molecules known to be present in olfactory receptors.
The researchers next used a method known as calcium imaging to show that the cultured taste cells respond to odor molecules in a manner similar to olfactory receptor cells.
Together, the findings provide the first demonstration of functional olfactory receptors in human taste cells, suggesting that olfactory receptors may play a role in the taste system by interacting with taste receptor cells on the tongue.
Supporting this possibility, other experiments demonstrated that a single taste cell can contain both taste and olfactory receptors.
“The presence of olfactory receptors and taste receptors in the same cell will provide us with exciting opportunities to study interactions between odor and taste stimuli on the tongue,” Dr. Ozdener said.
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Bilal Malik et al. Mammalian Taste Cells Express Functional Olfactory Receptors. Chemical Senses, published online April 24, 2019; doi: 10.1093/chemse/bjz019
